Butyriboletus persolidus (“Butter Bolete”)

Short, butter-yellow, oft-bulbous stem may have red-brown stains, esp. lower down. Yellow pores darken w/age & stain blue. Firm texture.

Description

Name in North American Boletes: Boletus appendiculatus

Genus: Butyriboletus

  • Genus 2: Boletus

Species: persolidus

  • Species 2: appendiculatus

Common Name: Butter Bolete

Tells:  Short, butter-yellow, oft-bulbous stem may have red-brown stains, esp. lower down. Yellow pores darken w/age & stain blue. Firm texture.

Other Information: Cap color varies from pale yellow to a more typical reddish brown. Pale- to rich-yellow cap flesh may blue slowly & erratically. The common name refers to the butter-yellow stem, which may have subtle netting up high by the pores. Like all Butter Boletes, this mushroom has a very firm and appealing texture. Likes oak.

Science Notes: DNA testing moved this mushroom from Boletus to a newly erected genus called “Butyriboletus” (“butyri” being latin for “butter” and this being one of the Butter Boletes). The species name “appendiculatus” is now reserved for a lookalike European species.

Edibility: Choice.

CHEMICAL TESTS:

  • NH4OH (Ammonia): Cap flesh turns blue.
  • KOH: Cap flesh turns pinkish.
  • FeSO4 (Iron Salts): No data.

Links:

National Audubon Society Field guide to Mushrooms, Gary Lincoff0Mushrooms of West Virginia and the Central Appalachians0North American Boletes91

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